2 for 1 - Giant Spider Invasionhttp://thumbnails.hulu.com/18/728/88...NgYB+eEVgg.jpg

I agree with much of what has already been posted,some others that are fun ...

Bad Taste
Evil Aliens
Altered
The Faculty (Yes really,It's fun)
Lifeforce

How could I forget Bad Taste? Super Gross!!http://1.bp.blogspot.com/_7jNPbVyDlY...0/BadTaste.jpg

Another 2 for 1 (Alien Invasion, Evil Plants). The Outer Limits episode Specimen Unknown:http://cdn1.ioffer.com/img/item/357/994/51/b4_7.JPG

Night Of The Creeps:http://movies.infinitecoolness.com/16/creeps07.jpg

Does Splinter fit?
 

I saw Splinter quite a while ago. I love that freaky movie. Its amazing how effective it was. It dont know if it fits here but I thought I would mention it. If you havent seen it I think youll get a kick out of it.

I did see it.

I'm not sure if it was meant to be an alien or homegrown contagion, but it was pretty cool.http://hannahpoturalski.files.wordpr...0/splinter.jpg

My all time fave, Galaxy Invader... low-budget underrated alien invasion!

I remember that film. It was featured in the opening credits of Pod People, an alien invasion Mystery Science Theater classic:http://4.bp.blogspot.com/_mVZ__QdOGQ...00/303Pod3.jpg

I quite liked that way that particularly the first half of Independence Day, the viewer is very unaware of the alien's real motives and such. I mean, for so long all we see of them is the enormous space ship. I felt that it captured the confusion that one would feel in such a situation quite well.